Pyrazole derivative



United States Patent 3,121,092 PYRAZOLE DERIVATIVE Adolph Oscar Geiszler, Mundelein, Ill., assignor to Abbott Laboratories, North Chicago, 111., a corporation of Illinois No Drawing. Filed Jan. 29, 1962, Ser. No. 169,652 1 Claim. (Cl. 260-310) This invention relates to S-cyano-l,3-dimethyl-4-nirtopyrazole of the formula HaC-il C-NO:

C-CN

which is then heated with an alkali metal cyanide, preferably potassium cyanide, at a temperature of 120130 C. in the presence of a solvent such as dirnethylformamide. Upon removal of the solvent and treatment of the residue with water, the mixture is acidified and coolant to precipitate the desired S-cyano-1,3-dimethyl-4-nitropyrazole which is purified by recrystallization from a suitable solvent, preferably a water-alcohol mixture.

The following example illustrates a specific embodiment of the invention and is not to be construed as limiting.

3,121,092 Patented Feb. 11, 1964 EXAMPLE 5 -Cyan0-1 ,3-Dimethyl4-N itropyrazole In the first step of the reaction, 155 ml. of fuming nitric acid was added slowly at from to 10 C. to a mixture of 200 ml. of concentrated sulfuric acid and 63 g. (0.48 mole) of 5-chloro-1,3-dimethylpyrazole. After standing at room temperature for 15 hours, the reaction mixture was poured into 2 liters of ice-Water. The white solid which formed was separated by filtration, Washed with Water and dried to obtain the intermediate S-chloro-1,3-dimethyl-4-nitropyraz0le melting at 77- 78 C.

In the second step of the reaction, a mixture of ml. of dimethylformamide, 3.6 g. (0.05 mole) of potassium cyanide and 8.8 g. (0.05 mole) of the intermediate prepared above was stirred and heated at -l30 C. for 4 hours and thereafter allowed to stand at room temperature for 17 hours. The solvent was then removed and the residue diluted with water. The aqueous solution was acidified and heated under reduced pressure to remove any hydrocyanic acid. Upon cooling, the desired 5- cyano-l,3-dimethyl-4-nitropyrazole precipitated and was removed by filtration. After washing with water and recrystallizing from a Water-ethanol mixture, the product melted at 98100 C.

What is claimed is:

S-cyano-1,3-dimethyl-4-nitropyrazole.

References Cited in the file of this patent UNITED STATES PATENTS 2,748,051 Zbornik et al May 29, 1956 2,759,949 Hitchings et a1. Aug. 21, 1956 2,827,415 Freeman et al Mar. 18, 1958 2,998,425 Dickinson et al Aug. 29, 1961 3,014,916 Wright Dec. 26, 1961 3,054,722 Wiegand et a1 Sept. 18, 1962 FOREIGN PATENTS 869,552 Great Britain May 31, 1961 OTHER REFERENCES Jacobs: Pyrazoles and Related Compounds In: Elderfield Heterocyclic Compounds, vol. 5, pp. 101-104, N.Y., Wiley.

Morgan et al.: Jour. Chem. Soc. (London), vol. 123, pp. 1308-18.

Knorr et al.: Liebigs Annalen der Chemie, vol. 279, pp. 228-29 (1894). 

